Just how steadfast is China’s support of North Korea? It is a question that has been asked by outsiders since the Korean Peninsula was divided after World War II. Given the secrecy of the two allies, concrete answers are hard to find. And wrong conclusions, as when General Douglas MacArthur and President Harry Truman underestimated China’s support for its communist ally when U.S.-led U.N. forces stormed north in 1950, can have disastrous consequences.

So it’s worth paying attention when Chinese President Xi Jinping weighs in on the issue, or at least appeared to, at the Boao Forum on the Chinese island of Hainan. “No one should be allowed to throw the region or even the whole world into chaos for selfish gains,” Xi said Sunday. The new Chinese leader didn’t single out North Korea, but given the near daily threats and provocations emerging from Pyongyang in recent weeks, it was seen by many observers as a likely target of the criticism.

The White House also seems to detect a shift in China’s support for North Korea, the New York Times has reported. But Gregory Kulacki, China project manager with the Union of Concerned Scientists argues that the U.S. media have exaggerated any movement in China’s stance. “The idea that China would change its policy on North Korea because of security concerns is so well-entrenched in the minds of U.S. officials and reporters that this ‘subtle change’ in China’s thinking about North Korea was taking place in a 2003 episode of The West Wing,” he wrote in a post on the All Things Nuclear blog.

The expectations go back even further than that. In the early 1990s, after the fall of the Soviet Union and China’s establishment of diplomatic ties with South Korea, discussions of Sino–North Korean ties frequently mentioned China’s growing anger. “The self-styled North Korean Great Leader, Kim Il Sung, sometimes describes China as his country’s ‘large rear area,'” the Times’ Nicholas Kristof wrote in a 1993 story headlined “China and North Korea: Not-So-Best of Friends.” “Mr. Kim does not mean any insult, and if he has a sense of humor he hides it better than his nuclear weapons program. But it is true enough that China these days feels that it is being treated as North Korea’s large rear area.”

Two decades, two North Korean leaders and three nuclear tests later, China is still perturbed with North Korea. A nuclear armed North Korea is frightening to Beijing, but so too is a unified, U.S.-aligned Korean Peninsula and the prospect of an unchecked flow of starving refugees crossing the Yalu River. For all its criticism of Pyongyang, Beijing is unlikely to push its brittle ally to the brink.

Two days after Xi’s speech, the overseas edition of the People’s Daily, the Chinese Communist Party’s mouthpiece, ran a front-page editorial discussing just who China’s leader was referencing when he complained about countries throwing the world into chaos for selfish gains. The first two specific cases named were Iraq and Afghanistan. “Some countries spend billions but still can’t fix the problem, can’t think of a way to exit and trigger their own fiscal and financial crises,” the paper wrote, in a clear reference to the U.S. It proceeded to scold the West for “fanning the flames” of unrest in the Middle East and North Africa and “outside nations or those who wish to interfere with China’s peaceful development” for stirring up problems in the East and South China seas. As for North Korea, it dismissed the situation in a sentence, saying merely the involved parties “should not seek the worst possible outcome.”